Among conventional electromagnetic relays and electromagnetic contactors functioning as contact devices for opening/closing current paths, various contact mechanisms have been proposed for extinguishing an arc that is generated when movable contactors and fixed contactors are opened to be separated from each other, in order to bring a closed state of the contact mechanisms where the fixed contactor and the movable contactor are in contact with each other, to an open state by interrupting a current.
For example, there is proposed an electromagnetic relay that has a pair of fixed contactors disposed away from each other by a predetermined distance, a movable contactor disposed to be capable of contacting with and separating from the pair of fixed contactors, and an electromagnetic block that drives the movable contactor. A U-shaped magnetic holding member is positioned on the outside of a sealing container that faces either side surface in a position where the fixed contactors and the movable contactor face each other, and two pairs of permanent magnets are positioned on the inside of the magnetic holding member in order to extinguish an arc easily by stretching the arc using a magnetic force of the permanent magnets (see Patent Document 1, for example).
However, although the arc can be stretched and extinguished easily by the magnetic force of the permanent magnets, the prior art described in above-mentioned Patent Document 1 has a problem where the gap between the pair of fixed contactors and the movable contactor needs to be enlarged in order to reliably eliminate the arc. Another problem is that a U-shaped magnetic supporting member and two pairs of the permanent magnets supported by the magnetic supporting member are required on the outside of the sealing container, which results in an increase in the number of parts and assembly processes, as well as the production costs.
In order to solve such problems, a sealed relay device is proposed in which arc discharge is extinguished in a configuration where a flat section is formed at a tip end of a semicircular contact part between a fixed contactor and a movable contactor contacting the fixed contactor, a permanent magnet is embedded in a direction perpendicular or parallel to the flat section, and a magnetic flux is formed in a direction perpendicular to an arc that is generated when the sealed relay device is in an open state (see Patent Document 2, for example).    Patent Document 1: Japanese Patent Application Publication No. 2010-10057    Patent Document 2: Japanese Patent No. 3733637